South African magnetic field barriers stop sharks 100%

These South African magnetic field barriers stop sharks 100% of the time – and they’ve just been installed in Reunion

A South African start-up has developed a shark barrier that the ocean predator will not cross.

It is made out of magnets and a fake kelp forest, and Reunion Island’s Shark Risk Reduction Resource and Support Center is testing it in the beach-goers paradise. It is also in Gansbaai in the Cape.

Great white sharks are vital for ocean ecosystems, but they are under threat – mainly from humans.

A South African invention is right now being tested on Reunion Island, with a view to protecting beach-goers without killing sharks and other marine life. TheSharkSafe Barrieris a non-harmful way of keeping sharks away from humans.

The barrier is made out of tubes containing strong magnets, and biomimics a kelp forest to visually deter sharks. Sharks are able to detect magnetic fields, thanks to sensory organs calledampullae of Lorenziniin their heads. These ampullae are a highly sensitive network of tiny jelly-filled pores that allow sharks to sense electromagnetic changes.

In waters off Gansbaai in the Western Cape, there was a 15m by 15m square circumscribed by a SharkSafe Barrier that no shark has crossed in the two years of testing — even though there was food inside it. “In all the years of experiment, they never crossed it,” says Sara Andreotti, one of the inventors. And it wasn’t just great white sharks, but also bull, tiger, and hammerhead sharks.

“Between 2011 and 2016, there have been 491 registered shark attacks worldwide, of which 43 proved to be fatal,” Andreottihas said. “Over the past 20 years, however, almost 4,000 sea creatures have been in shark nets lining the beaches of New South Wales in Australia alone.”

There has been a move towards non-invasive ways to keep sharks and people separate. In Cape Town,the Shark Spotters programmehas people watching the ocean, ready to alert swimmers to the presence of sharks.

Research on South Africa’s great white shark population — undertaken by Andreotti as part of her doctorate at Stellenbosch University — found that the population has particularly low genetic diversity. Genetic diversity is important because it indicates a population’s resilience: if there is an environmental change or if a disease sweeps through the population, it will be more likely to survive if there is greater genetic diversity.

The more sharks that die in nets, the more diluted that diversity gets.